Kokoro Amatsu (天津 心 Amatsu Kokoro) is the Aoba High School's Girls Volleyball team Coach and the class teacher of class 3-3 at Aoba High School.
Kokoro Amatsu has short brown hair, parted in the middle. It is usually tied in a short ponytail with a few stay hairs framing her face on one side. She has a set of brown eyes and light skin. She has a slim and short stature.
Kokoru usually wears sports related clothes as Physical Education is her subject.
She appears to be an energetic, caring teacher and keeps all her students under control, even though she is one of the youngest teachers at the school. She gives advice to her students and is quite mature.
She graduated from the same university as Kōshi Usa. She is a new teacher at Aoba High School and class 3-3 was the first class under her.
He is her fellow colleague in Aoba High School. They graduated from the same university and are very good friends.
She is her fellow colleague. The duo have a good relationship with each other.